1、An American National StandardPublished by the American Nuclear Society 555 N. Kensington AveLa Grange Park, IL 60526ANSI/ANS-2.6-2018Guidelines IRU Estimating Present these procedures are accredited by the American National Standards Institute, Inc., as meeting the criteria for American National Sta
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9、6-2018 with permission of the publisher, the American Nuclear Society.” Reproduction prohibited under copyright convention unless written permission is granted by the American Nuclear Society.Printed in the United States of AmericaAmerican National Standard ANSI/ANS-2.6-2018Inquiry RequestsInquiryFo
10、rmatThe American Nuclear Society (ANS) Standards Committee will provide responses to inquiries about requirements, recommendations, and/or permissive statements (i.e., “shall,” “should,” and “may,” respectively) in American National Standards that are developed and approved by ANS. Responses to inqu
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14、tated in a clear, concise manner;(5) a proposed reply, if the inquirer is in a position to offer one. Inquiries should be addressed to: American Nuclear SocietyScientific Publications and Standards Department555 N. Kensington Avenue La Grange Park, IL 60526 or standardsans.orgAmerican National Stand
15、ard ANSI/ANS-2.6-2018American National Standard ANSI/ANS-2.6-2018iForeword(This foreword is not a part of American National Standard “Guidelines for Estimating Present the word “should” is used to denote a recommendation; and the word “may” is used to denote permission, neither a requirement nor a r
16、ecommendation.1)The current standard, ANSI/ANS-2.6-2018, is hereinafter referred to as “this standard.”2)Numbers in brackets refer to corresponding reference numbers in Sec. 7, “References.”American National Standard ANSI/ANS-2.6-201822.2 Definitionsapportioning: The process of distributing populati
17、on data from a dataset where data are aggregated in geographic units (e.g., census tracts or block groups) that do not match the polygon shape of the defined areas within the study area (e.g., sectors or uniform grid squares).area-ratio method: A method of apportioning the population data whereby th
18、e population of a defined area (e.g., sectors or uniform grid squares) is expressed as a relative proportion of population of a larger geographic unit (e.g., a census tract or block group) in which the defined area is located.base year: The year from which the demographic data used in the analysis o
19、riginated. Most typically it is the most recent census data.census block: The smallest area for which the United States collects population data. Census blocks are bounded by visible features, such as streets, roads, streams, and railroad tracks, and by nonvisible boundaries, such as selected proper
20、ty lines and city, township, school district, and county limits and short line-of-sight extensions of streets and roads. Generally, census blocks are small in areafor example, a block in a city bounded on all sides by streets, but census blocks in suburban and rural areas can be large.In remote area
21、s, census blocks can encompass hundreds of square miles. Census blocks cover the United States and its territories. Census blocks nest within all other tabulated Census Bureau geographic unitsand are the basis for all tabulated data.census block group: A statistical division consisting of one or mor
22、e census blocks generally defined to contain between 600 and 3000 people.Census Bureau geographic unit: The term means any of the following: block, block group, county, county equivalent, census county divisions, census tract, enumeration district, incorporated places (e.g., cities or villages), min
23、or civil division (e.g., town or township), or state. census tract: A small, relatively permanent statistical subdivision of a county delineated by a local committee of census data users to provide a stable set of geographic units for the presentation of statistical data. Census tracts nest within c
24、ounties, and their boundaries normally follow visible features but may also follow legal geographic boundaries.centroid: Arithmetic mean position of all the points in a plane figure or two-dimensional shape. The definition extends to any object in n-dimensional space, where its centroid is the mean
25、position of all points in all coordinate directions.centroid method: A method of apportioning population data whereby the entire population of a census unit (e.g., census block) is assumed to be located at the centroid of the census unit (e.g., census block).dasymetric mapping method: A geospatial t
26、echnique that distributes data that have been assigned to arbitrary boundaries, such as census blocks, using additional information, such as land use data, to apportion population by land use and cover. See Appendix C.4 and Fig. C.5.forecast: A population projection that is useful for analytical, pl
27、anning, or policy purposes accompanied by a judgment regarding its accuracy.forecast year: Year for which the demographic data are needed for siting purposes. The forecast year is typically the year when construction starts.geographic coordinate system: The use of a three-dimensional spherical surfa
28、ce to define locations on the Earth, including a horizontal, a vertical, and an elevation measurement.American National Standard ANSI/ANS-2.6-20183geographic information system (GIS): A mapping system, typically computer-based, used to visualize, question, analyze, and interpret geospatial data and
29、display it in useful ways.North American Datum of 1927 (NAD 27): The use of mathematical triangulation of about 250,000survey stations across the United States and Canada to precisely identify the position of any other position in North America. Most historical United States Geological Survey (USGS)
30、 topographic maps and projects by the U.S. Army Corps of Engineers used NAD 27 as a national reference system.North American Datum of 1983 (NAD 83): A unified horizontal or geometric datum and successor to NAD 27 providing a spatial reference for Canada and the United States. It is the most current
31、datum being used in North America and provides latitude, longitude, and elevation information to form the basis of latitude and longitude coordinates for all horizontal positions for Canada and the United States.nonhabitable lands: Lands within a study area that ordinarily would be considered as par
32、t of the denominator of a population density calculation but are inappropriate for consideration because they cannot be reasonably considered suitable for human habitation in the foreseeable future, such as large water bodies, national park lands, and similar large tracts.permanent resident populati
33、on: The persons who live or sleep most of the time in a study area, which is not necessarily the same as the place of legal residence. population: See “total population.”population density: The population (actual count or estimate) divided by the total area of the study area.population estimate: A s
34、ubstitute for a complete count of a population.population projection: A calculation of the future size of a population if a given set of assumptions, such as the behavior of births, deaths, and migration, holds.projected coordinate system: A system that projects angular latitude and longitude point
35、locations from a sphere onto a flat surface.sector: A closed, four-sided segment of area in a polar coordinate system map, constructed from two adjacent concentric arc segments and two adjacent radial (i.e., directional) lines, resembling an arc-shaped rectangle. For the innermost circle of the map,
36、 a segment would be the closed pie-shaped “triangle” created by the center point, two adjacent radial lines, and an arc segment of the first ring.sector map: a polar coordinate system overlaid onto a topographical, geopolitical, or other two-dimensional map.state plane projection: A group of planar
37、coordinate systems based on the division of the United States into more than 130 zones to minimize distortion caused by map projections. Each zone has its own map projection and parameters and uses NAD 27, NAD 83, or WGS 84 horizontal datum. The Lambert conformal conic projection is used for states
38、that extend mostly eastwest, while transverse Mercator is used for those that extend mostly northsouth. The oblique Mercator projection is used for the panhandle of Alaska.study area: Area for which a population estimate or forecast is being made. It can be a political boundary; a defined space, suc
39、h as an emergency planning zone; a census geographic unit; or any other boundary.total population: The sum of the permanent resident population plus any transient population (in-commuting workers and any visitors) that may be present in the study area.American National Standard ANSI/ANS-2.6-20184tra
40、nsient population: Tourists, shoppers, workers, and other people who do not reside within the study area and are visiting the area for recreational purposes at transient attractions (e.g., parks, beaches, sport stadiums, concerts, etc.) or for employment at an employer located within the study area.
41、 For demographic calculations, it is assumed that the transient population is not counted as part of the permanent population.uniform grid map: A grid composed of a square with sides of uniform length, with the middle square vertically and horizontally centered on the site under study (e.g., a nucle
42、ar power plant site), and having contiguous squares extending outward in all directions to cover all parts of the circle that constitutes the study area.uniform grid squares: The individual squares that comprise a uniform grid map, all of which have the same dimensions and completely overlay the stu
43、dy area.World Geodetic System (WGS 84): The reference coordinate system used by the Global Positioning System. It is an extremely precise Earth measurement across continents and oceans, using satellite radio wave transmissions to establish locational coordinates for any point on the surface of the E
44、arth with an error of less than 2 centimeters to the Earths center mass.2.3 Acronyms CFR: Code of Federal RegulationsGIS: geographic information systemNAD 27: North American Datum of 1927NAD 83: North American Datum of 1983 USGS: United States Geological SurveyWGS 84: World Geodetic System3 Pre-anal
45、ysis decisionsPrior to undertaking a demographic analysis, the analyst shall identify the proposed nuclear site and determine the size and location of the study area. The size of the study area shall be determined based on appropriate federal regulations, guidance, and standards.3.1 Defining the gri
46、d patternOnce the location of the site and the size of the study area have been identified, the analyst shall select a grid pattern compatible with the geographic information system (GIS) mapping software to be used. The grid pattern partitions the study area into smaller defined areas that allow fo
47、r greater disaggregation of demographic information. The analyst shall use a projected coordinate system to model population. The grid pattern shall be one of two alternatives: (1) a sector map, or (2) a uniform grid map.3.1.1 Sector mapTo develop a sector map, the analyst shall:x draw a series of c
48、oncentric circles centered on the proposed site with radii increasing in 1-km (0.6-mi) increments;American National Standard ANSI/ANS-2.6-20185x draw lines from the center of the circles in 4 cardinal (north, south, east, and west) and 12intercardinal (north-northeast, northeast, east-northeast, etc
49、.) directions;x develop sectors by establishing arc segments with linear boundaries that bisect each of the 16 radial lines, so that the north, south, east, west, and the twelve intercardinal lines become thecenterline of each segment).For example, if 10 circles of 1-km (0.6-mi) depth are drawn out to 10 km (6 mi) from the center of the study area, this creates 160 sectors (16 directions 10 rings). All sectors within a ring shall have the same area. Figure 1 presents an example of a sector map around a hypothetical nuclear site. Figure 1 Sector map example. Image used with pe
